Limitation of 3547 to 1182 conversion efficiency in Xe

We report experiments which indicate that the 3547 → 1182A conversion efficiency in Xe-Ar mixtures is limited by Kerr-induced dispersion to about 0.9 percent. The mixed frequency third-order nonlinearity \chi^{(3)}(-3\omega, 3\omega, -\omega, \omega ) significantly alters the index of refraction at 1182 A in the presence of large power densities at 3547 A, affecting phase matching. We suggest using a Xe-Mg-Ar mixture to reduce the effect, thus permitting increased efficiencies.